Polyethylene glycol or PEG of the formula H(OCH2CH2)n-OH with n equal to 4 to 900 corresponding to average molar masses of from 180 to 40000 g/mol, are generally prepared by polymerizing ethylene oxide with water or polyhydric alcohols. Ethoxylate esters and particularly esters of PEGs are employed in a large number of areas and applications because of their interesting properties. A large number of these applications involve the polyethylene glycol ester making superficial contact with the skin of living creatures, especially humans, or being administered orally or parenterally to humans or animals. Examples of such applications are solvents for active ingredients, flavorings or fragrances in medicinal drops, solutions for injection, dietary supplements, tablets, ointments, sticks, suppositories or gelatin capsules; plasticizers for coatings of film-coated tablets; binders in tablets; humectants in toothpastes; moisturizers and/or conditioners in shower preparations, shampoos, cream rinses, hair treatments, soaps, liquid soaps, hair sprays, hair gels, after-shave products, face packs, sunscreen products, creams or lotions; ingredient of multiphase products such as two-phase shower preparations, two-phase foam baths or three-phase bath oils; and active ingredient in eye drops, laxatives or solutions having antiapoptotic activity.
Alcohol ethoxylates and PEGs by themselves are not genotoxic, mutagenic, carcinogenic or sensitizers and are readily biodegraded. When ethoxylate esters are made with a traditional chemical process, exposure of an ethoxylated intermediate to heat and acidic conditions can lead to the formation of the carcinogenic byproduct 1,4-dioxane. Trace levels of 1,4-dioxane have raised concerns about the use of ethoxylated surfactants in formulated home, laundry and personal care products.
The amount of 1,4-dioxane that is allowed to be produced by a production plant can be limited by specified concessions. In these cases, a limit on the amount of 1,4-dioxane thus leads indirectly to a limit on the production capacity of a ester polyol production plant. The 1,4-dioxane formed as a by-product also has the effect of reducing the yield of the desired product, since, as described, part of the diethylene glycol used is removed from the reaction mixture in the form of 1,4-dioxane instead of being incorporated into the ester produced.
Accordingly, there is a need for fully acylated polyoxyalkylene ester composition having less than about 20 ppm of 1,4-dioxane and having a high molar yield of the fully acylated ester constituent. There is also a need for a process of making a fully acylated polyoxyalkylene ester composition.